Different psychologists have described this operational definition. However, it is an agreed fact that predicting future achievement is much more difficult than present achievement. According to Aiken (1985: p.453) an aptitude test is, “A measure of person’s ability to profit from further training or experience in an occupation or skill.” Woodworth and Marquis (1963: p.26) described it in a different way, “An aptitude test, in itself, is nothing more than an achievement test, but it is used not simply as a measure of present performance in the special task but as an index of future performance in other and broader tasks.” Wiersma (1986: p.302), “An aptitude test gives indirect evidence of the existence of the potential.” The major object of aptitude testing is to measure varied capacities and potentialities of individuals. It may be difficult in the measurement to separate potential from actual achievement.